Harvesting solar energy for vapor generation is an appealing technology that enables substantial eco-friendly applications to overcome the long-standing global challenge of water and energy crisis. Nonetheless, an undesirable low light utilization efficiency and large heat losses impede their practical use. Here, we demonstrate a typical design paradigm capable of achieving superb nonconvective flow assisted water collecting rates of 2.09 kg/m2h under 1 sun irradiation with a high photothermal conversion efficiency of up to 97.6%. The high performance is ensured by an elaborately constructed coaxial copper@polypyrrole nanowire aerogel with surpassing photons acquisition and thermal localization capabilities. Using state-of-the-art micro-/nanoscale measurements and multiphysics calculations, we show that the metallic copper nanowire core can effectively excite surface plasmon resonance, which induces swift relaxation dynamics to achieve a highly efficient light-to-heat conversion process. A thin polypyrrole layer dramatically enhances broadband light absorption with minimized infrared radiation and low thermal conduction, leading to an impressive local heat concentration as high as 220 °C under 4 sun irradiation. Engineered empty space inside aerogel assembly of building blocks further facilitates large light penetration depth, smooth mass transfer, and robust mechanical capacity for synergistically boosting actual presentation. This work provides not only a rational design principle to create sophisticated solar-thermal materials but also critical information that complements insights about heat generation and temperature confinement in a scale-span system during strong light-matter interaction processes.
Keywords: aerogel; copper@polypyrrole nanowire; hot electron; solar evaporation; surface plasmon resonance.